Coolant flow

[SamB]

Hi, not sure if this is the right area to post this question in!?!?

I'm at the stage of hooking up the coolant and heater hoses and was wondering which way round the heater hoses should be connected to the 1U.

Does the inlet to the heater go on to the pipe from the thermostat housing or the rear alloy crossover pipe??

Help!!

 

[gloverman]

heater inlet (hot water ) from the rear crossover pipe and returned to the waterpump via the steel tube which goes under the intake manifold. As a general rule hot is at the top and cold lower. Cheers

 

[SamB]

Thanks, makes sense!!

 

[cribbj]

Here's a related question, can someone tell me where connections #1 & #2 (see photo below) go on the front water bridge?

#2 looks like it would go to the coolant overflow tank, which I think for the Lexus is pressurised? For my Supra swap, the coolant overflow bottle is not pressurised.

Wonder if it should be connected anyway, just to ensure the engine stays full of coolant and free of trapped air?

#1 looks like it might go to the throttle body to keep it warm for anti-icing?

Also, at the bottom of this bridge, there's a flanged connection where it mates with the water pump. Is there normally a paper gasket there, or is it only FIPG?

Thanks in advance.

 

[elhsupra]

I think two goes to the ISC
One to the pressurized overflow

 

[cribbj]

Thanks Eric, so the larger connection goes to the ISC, while the smaller one is like a vent and it goes to the overflow?

I'm now thinking that #1 shouldn't be connected for my swap as my overflow bottle isn't pressurised, nor is it the highest point in the system. Looking at the coolant flow diagram, there's that #1 connection from the suction side of the water pump to the reservoir, then there's another connection from the discharge side of the pump to the reservoir, and and with these two there's circulation of coolant in the reservoir.

I think I'm going to pull both those nipples and plug the holes, along with pulling the two small nipples and plugging the ports on the rear bridge.